Ignitee



P. BROWN.

Patented June 24, 1919.

- ATTORNEYfZI UN TED STATES PATENT onnros;

PHELPS BROWN, 01? SPRINGFIELD, MASSACHUSETTS.

IGNITER.

Specification of Letters Patent.

Patented June 24,. 1919.

Application filed October 24, 1918. Serial No. 259,530.

commercial exploitation of reciprocating igniters has, however, been hampered, and

their field of service considerably restricted, owing to the fact that they have, heretofore,

been notoriously noisy in operation. The

factors, which contribute largely in the production of the noise, are nevertheless desirable since they permit certain advantages in operation, which are otherwise not obtainable, so far as I am aware, by igniters of other types. For example, in reciprocating igniters, an armature is reciprocated to and from a core, as by a cam which forces the armature into engagement with the core and then releases it for movement at hlgh speed away from the core. The latter movement is wholly independent of engine speed and thus the intensity of the spark produced on such movement is not, as in other types of igniters, dependent upon the speed ofthe cngine. This is avery important and advantageous feature of the reciprocating igniter, but the very mechanism, which permits this desirable feature to be obtained, also pro- 'duces a great deal of undesirable noisc due to the impingement of various bodies movng at the high speeds necessary for the citiclent generation of current. It has been attempted to eliminate such impingement by the use of sliding contact between the core and armature. It will be seen at once, however, that the rate of change of magnetic flux must of necessity be much less when a sliding contact is employed than when the armature and core are disengaged in an axial direction, assuming like armature driving power and like cross-sectional area of the magnetic circuit.

This invention is concerned, among other things, with, and has for its broad object, the provision of a reciprocating igniter which retains the important advantage as to high speed actuation of the armature independently of engine speed, and yet obtains this advantage in such a manner that practically all of the noise, which has heretofore characterized igniters of this type, is eliminated.

According to-another featureof the invention, the relatively movable magnetic members of the igniter, which produce the flux variations, are separable for a predetermined distance by resilient means, and a non-yielding reciprocable element, having a stroke greater than said distance, is provided to effeet an engagement of said members, together with means permitting a relative yield between the engaged members and said element for the purpose of absorbing the ex cess travel of the latter, the last-named means being arranged to oppose the compression of the resilient means.

According to another feature of the in.- vention, improved actuating means are provided for moving the armature into and out of engagement with thecore, which means includes resilient elements arranged to act in opposition on the armature and a reciprocable element connected to the armature through one of the resilient elements.

According to the last-named feature of the invention, the reciprocable element transmits its force through the stronger of a pair of oppositely acting resilient elements and as the armature is 'moved toward the core the weaker resilient element becomes gradually compressed. The other resilient element does not become compressed until the arma- .tm'e nears the core, but at such time does bccome compressed for the purpose of retarding the movement of the armature produced by the reciprocable element. In this retarding movement, the two resilient members", acting oppositely on the armature, equaiize one another, and the'armaturc is eventualiy and gently and firmly engaged with thecore.

According to another feature of the inven- 'tion, the stroke of the reciprocable 'armature actuating element is made greater than the lift of the armature and, after the latter has been seated as described, the 1 excess stroke of the reciprocable element is absorbed by the stronger of the two resilient elements. This results in the creation of an appreciable time interval, during which the armature is seated on'the core, and such time interval is desirable in order that the mag netic circuit through the core and mi tu e may become fully established, at

rangement also insures that the armature is held tightly seated against the core despite wear in the parts, as in the reciprocable element. Were the latter of'a stroke just equal to the lift of the armature, it would not be able to tightly seat the Jmature after'it had become shortened through wear.

According to another feature of the in vention, the igniter is of the type wherein the flux from a magnetic source is alternately directed through and shunted away from the generating winding, and this arrangement is characterized by the use of only one armature actuated as described, the shunting being accomplished by a pen manent shunt of relatively high reluctance.

Although this arrangement results in cer-q tainlosscs, such losses are more than otfset by the advantages obtained in IHCIQRSOCl quietness of operation. and, by employing secondary windings, in addition to the pri mary windings, sparks, of ample intensity for all practical purposes, may be produced.

According to the last-named feature of the invention, coiipcrating; breaker points are necessary'to interrupt the primary circuit when the current therein reaches its maximum valve, in order that a current may i be induced in the secondary winding. The

provision of an interrupter wnich will auto- Figure lis a top plan view of an igniter embodying the invention;

F ig. 2- is an elevational view thereof with certain parts broken away;

Fig. 3 is a cross-sectional View taken on the line 33of- 1;

tageously used. Such inechams source of malrnetic lies, as a iF-igs. 41 and 5 are sectional plan. views taken on the lines JP-4: and 5 5, respectively','of Fig. 3; and

F 1g; 6 1s a diagrammatical view illustrative of the electral connections of the igniter.

-In these drawings, there has been shown one type of igniter with which the invention may employed and, while the illustrated type is desirable and'advantageous (and therefore in a measure preferred), the invention-is, nevertheless, independent of the particular igniter structure, as to ceitain features]; Particularly, as to the armature actuating" mechanism, the specific igniter structure, hereinafter to be described, is to .be taken merely by Way of illustrative example of onestructure with which the arma-.

ture. actuating mechanism may advanisi obviouely,'-equally capable of use tynes of ign-iters, if desired,

The ignite; includes, wscntially, a suitable 'by awire 16 (Fig. 6).

i then be the termina ary coils 17 and 18 superimposed on the primary coils 11 and; 15, respectively. It the secondary winding is to be employed, the coils 17 and 18 are suitably connected electrically, as in series by a wire 19 (Fig. The supply terminals of the igniter will t the secondary wind ing', as the wires 20 21, being preferabiy grounded in accordance with the usual custom. The terminals of the primary winding are, when the sec;- ondary winding is used, electrically connected, as by wires and 23, to cooperating breaker points 2% aiid 25 of an interrupt-er mechanism to be later described, which breaker points are automatically sepa- "able' when the current in the primary winding reaches its maximum value to induce 'an olectro-motive force in the secondary winding. denser 26 is bridged across the breaker points Qiand 25.

The cores 12 and 14 are preferably provided with ugper and right angularly turned extensions 2;: and 28 which extend toward one another with their ends in closely ad- ]acent relation, so that a permanent air gap '29 is provided. The source of magnetic flux, as a magnet 10, has one magnetic pole magnetically connected to one core and the other similarly connected to the other core.'

and cores 12 and 14 are in engagemenhthe major portion of the flux from source l0 flows through that path which includes the cores and thus the primary generating wind mg 18 encircled.

TWhen the armature and cores are separated s that the double air gap between them maneut air gap 29, t the flux is shun-zed a majorportion or" ay the cores 12 The two coils are id 21, one, as the wire Preferably; as is usual, a conater than the perchosen to illustrate 'taining bolts 32.

concerned, will now be described.

and 14 and flows through the extensions 27 and 2S and across the permanent air gap 2 Other means may be provided for accomplishing a shunting of the'flux from the generating windings, if desired, and the means, the invention, although desirable and in a measure preferred, a re not essential for all purposes. Particularly the armature actuating mechanism is generally applicable, even to igniters wherein no shunting of the flux occurs.

heferring now the detailed mechanical structure of the igniter and the mounting of the several elements described; such structure and the means chosen to assemble such elements may, obviously, be varied in many particulars, and the following description is,-

therefore, to be taken as merely illustrative. The cores 12 and 14, and their extensions 27 and 28, are preferably made up of laminations in the usual manner, as indicated in Fig. 1. At the lower end of each core, a pair of angle-shaped blocks 30 (Fig. 5) partially encompass the laminations of the core, and each block of one pair is connected to the corresponding block of'the other pair by a cross-bar 31 of non-magnetic material. The cross-bars, blocks, and laminations of the cores are the'n'clamped together by rehe coils 11 and 17 are mounted on core 12 above the cross-bar 31, and the coils 15 and 18 are mounted on core 14, also above the cross-bar. Above the coils, the cores 12 and 14 are connected together by one or more magnets 10 (blocks 33 and bolts 34, similar to the blocks and bolts just described, being employed). As shown, two magnets are employed one on each side of the cores, although, obviously, as many magnets may be employed as is necessary or desired. The magnets 10 and cross-bars 31 serve to space the cores 12 and 14, one from the other, and to tie them together into an assembled structure, and brackets 35, connected to the blocks 30, serve as a means for supporting this assembled structure from a suit-able base frame A. Mounted in the latter is a shaft 36, from which the armature actuating means is operated, as will appear, and such shaft may be driven at any desired speed in the illustrated direction by any suitable means (not shown).

The armature actuating means, with which the present invention is more particularly The ar mature 13, as shown in Fig. 4, is made up of laminations which are so bent as to afford a central opening to receive a bushing 37. On each side of such bushing, the laminations of the armature are clamped together by suitable means, as the retaining bolts 38, and by this means the bushing is firmly held to the armature. The bushing 37 is slidable vertically in a guide block 39 secured to the described cross-bars 31. The upper end of spring 48, but will raise rablc the bushing may also, as shown, be arranged to slide in a hole 40 in a member 41 of nonmagi'ietic material suitably secured to any stationary part of the igniter, as the magnets 10, for example. Within the bushing 37 and intermediate its ends is a suitably fixed block 42. Aspiring 43 acts between the base of hole 40 and the block 42 and tends to force the latter, bushing 37, and the armature 13 downwardly away from the cores 12 and 14. A flat spring 44, the ends of which are-supported by frame A, as shown in Fig. 3, limits the downward movement of the armature and serves as a cushion to absorb the shock incident to the sudden arrestation of rapidly moving armature.

The armature 13 is moved upwardly by a cam 46 on the described drive shaft 36. A cam follower, in the shape of a rod 47, rides on the periphery and is slidable in the lower portion of the bushing 37. A spring 48 is interposed between the upper end of rod 47 and the lower face of block 42 and, as shown, the ends of the spring may be connected to both the rod and block so that the former is suspended in the bushing 37. The spring 48 is stronger than the spring 43 so that an upward movement of rod 47 will not at first compress the bushing 37, and thus armature 13, until the latter hasbecn moved nearly into engagement with the cores. The compression of spring 48 may and preferably does continue after the engagement of the armature and core, as will be observed from Fig. 3, which shows the cam to have a greater rise than the lift of armature 13. The cam 46 is constructed with a sharp let-off portion 49, whiclrperiodically allows rod 47 to descend under the force of spring 48 and thus allows the bushing 37 to be moved downwardly by spring 43 of cam 46 and is guided by to carry armature 13 away from the cores.

The relative movement of rod 47 and bushing 37 by reason of spring 48 is limited by the degree of expansion of the latter, the rod being preferably, as described, prevented from falling from the bushing. This latter arrangement. is important since, as shown in Fig. 3, the rod 47 is thereby prevented from impinging on the heel of cam 46 in its downward flight.

The interruptermechanism is actuated by some reciprocable part ofjiiic igniter. as. for example, armature 13. One ln'eakcr point, as 24, is adjustably secured to a bracket 50, suitably secured to and insulated from frame A, and the other, is '25.; is carried on one end of a lever 51 pivotally supported interspring 53 tends to hold the. breaker points 24 and 25 in engagement. and thev are sepaduring the downward flight of armature 13 when one of the bolts 38 engages the other arm of lever 51.

The general operation of the igniter will largely appear from the foregoing description. To briefly summarize such operation, it will be seen that With armature 13 in engagementwith cores 12 and 14, a magnetic circuit of low reluctance exists through the cores and armature from the magnetic source 10. The other available path for flux to flow from the latter is through the extensions 27 and 28 and the permanent air gap 29, but, since this path is of relatively high reluctance, the major portionot' the flux encircles the generating windingon cores 1?. and 14 However, a-fte' armature 13 has been moved away from. the cores, the reluctance of the described shunt path is smaller than that of the path, which includes the cores and ari'nature together with the large double air gap therebetwcen, and accordingly the major portion of the flux is sln'nited away from the generating windings. Thus, on movement of the armature away from the cores (which movement is accomplished at high speed), there is a change of flux in the cores 12 and 14, and such change, as is well known, results in the generation of an. electro-motive force in the primary coils l1 and 15. 4

The induction of an elcctro-motive force in the secondary coils 17 and 18 results when the cooperating breaker points 24 and are separated. separation should, of course, occur at the time when the current flowing in the primary winding reaches its maximum value. Although the desirability of separating the breaker points at such time is obvious, I have foundthat the provision of means which will actually effect the de sired result at the right time are not so ob vious. In reciprocating igniters, there are several factors which have an important bearing on the time when the breaker points should be separated. Various lagging influences exist which tend to deter the time when maximum current exists in the primary winding, so that an interruption of the primary circuit at the time, when apparently the break should occur, does not in fact efi'ect maximum results as to induced electro-motive force in the secondary winding. For one-thing, the movement of the armature away from the cores does not result in an immediate cessation of flux as might be expected, and the operation of the interrupter must, therefore, be postponed until the armature has been disengaged from the cores for a.predetermined interval. Other tactors,,such as inductance in the primary winding or lagging by reason of the peculiar shunting means employed, may also contribute toward the creation of an appreciable-time'interval, during which a separation of the breaker points will not effect the induction of a maximum voltage in the secondary Winding. In the present igniter,

the lever 51 has been purposely spaced from its actuatin bolt 38 to compensate for the lagging int uences, which obtain, and to cause the break to occur with close accuracy at the time when maximum current is flowing in the primary winding.

The operation of the armature actuating means, which constitutes one of the most important features of this invention, will now be described. It will be seen from Fig. 3 that, with the parts in the relative positions illustrated, the end of rod 47 does not engage the heel of cam 46. This is important since the rod 47 cannot impinge on the cam and produce noise. As distinguished from the usual arrangement, wherein the rod and cam are. already engaged, the rod is gradually picked up as the cam rotates from the illustrated position, and the engagement of the rod andcam is, thus, largely a sliding engagement and, therefore, quiet. As the cam 46 continues to turn in the illustrated direction, the rod 47 is eventually lifted, and the rising of the rod acting through the stronger spring 48 raises armature 18. The rising movement of the latter is at first substantially proportionate to that of rod 47 since spring 48 does not become at all compressed until spring 43 has been first com pressed to a considerable degree. Eventually, however, spring -43 will become com" pressed to such an extent as to present a resistance equal to that of spring 43. and continued movement of rod 47 upwardly will then compress each spring until the armature- 13 engages the cores 12 and 14. Further movement of rod 47 will, of course, compress spring 48 only, the armature 13 being held against further movement by engagement with the cores. As the cam 46 continues to turn, it will eventually ride out from under rod 47, thereby allowing the lat ter to drop. This results in an expansion of spring 48 to a predetermined and limited extent and an expansion of spring 43, which drives armature 13 rapidly downwardly until it is arrested by the cushion spring The latter is so located as to arrest the arma ture before the rod 47, which travels with it. can impinge-on the cam.

It is particularly to be noted that spring 44 is always engaged with the armature 13. l/Vhen the lattcris engaged with the cores, the spring 44 is under little, if any, tension and is, therefore, readily flexed by the expansion of spring 43. However, as the latter expands and its tension decreases, the tension of spring 4-4 increases, and thus the latter eventually arrests armature 13. A. feature of importance is the constant engagen'ient of the armature 13 with spring 44, and. this is particularly advantageous since it eliminates all possibility of a noise producing impingement of the former on the latter.

hie of the most important results, obtained by the armature actuating mechanism described, is a gentle, quiet, yet firm,

seating of the armature upon its cores. The

interposition of the spring'48 between the reciprocable element 47 and armature l3 may be said to absorb some of the motion of the element 4?? toward the end of its upward stroke. That is, the full movement of rod 52-7 is not communicated to the armature as it nears the cores, and the result is a gradual decrease in its speed. The armature is brought slowly to rest and is gently laid upon and firmly pressed against the cores. The tendency of the armature to rapidly move into abutment with the cores due to magnetic attraction is resisted by .the spring Thus, the usual loud clatter of engagement ofarmature and core is avoided. The

spring d3, of course, opposes the upward force exerted by rod 47 as well as the magnetic pull described, but its opposition is of a yielding nature and is accompanied by a yield in the armature lifting mechanism itself, The spring 48 gradual-1y yields as the opposition from spring 4C3 increases, and

the two springs constantly seek to become balanced. Thus, the one spring constantly tends to push the armature toward the core as while the other tends to push it away, the armature for any given vertical position of red at? finding a balance between these two sprii s. A further increment of movement of rod disturbs this balance, rendering nec ssary a new adjustment between the two oppos ng factors, Meanwhile, the armature gradually decreases in speed'by reason of the compression of spring 48, and its re-. tarded approach coupled with the balancing action of the opposed springs results in the armature being engaged with the 'cores with practically no noise. Y

has already been pointed out that the red at? is efi'ectually prevented from impingeinent on cam s6 and that the downward flight of armature 13 is yieldingly arrested by the resilient cushion spring 44. Thus, t'ie movement of the armature on its hi h sneei stroze is efiectually quieted as 1 stroke.

important feature of the mechanism consists in whereby the armature lifta This is important since it is definitely insured that the armature will e tightly held to the cores even after parts (as the cam 16, rod .27, and so forth) have become worn. Were the yielding connection 41-8 omitted, it wiil be apparent t iat an origie 'i'ectseating of the armature on its would soon be destroyed by reason of Not only this, but the seating of the ture is momentary, and disengagement is liable to occur before magnetic circuit er has a greater travel than the v has become fully established. The present arrangement is characterized in that, not only is compensation provided for necessary wear in the actuating mechanism, but a definite time interval is created durin which the armature is held tightly seats on its cores to insure the full establislnnent of the magnetic circuit prior to disengagement of the armature.

The described method of slowly seating. the armature on its cores is most desirable for, as pointed out, the seating may be quietly effected. However, another advantageous feature-is obtained by'reason of the peculiar manner of seating the armature. The possibility of a relatively small and undesired spark being produced on the upward movement of the armature is entirely eliminated by the retardation of the armature at the end of its upward stroke.

Thus, I have provided an igniter which is characterized, among other things, by imp'roved means for actuating the armature at high speed yet quietly despite the repeated engagement of metallic armature and cores.

The invent-ion has been disclosed herein in one embodiment for illustrative purposes,

but the scope of the invention is defined by the appended claims rather than by the fore oing description;

Wile; I claim 1. In an igniter, relatively separable magnetic members coperating with one another to vary the reluctance of a magnetic circuit, means to move one of said members to ward the other, compremi-ble means to move the one member away from the other, said first-named means having a travel greater than the distance of separation of said members, and resilient means to absorb the excess travel of said first-named means, said resilient means opposing the compression 0 the second-named means. I e

2. In an igniter, relatively separable magnetic members coiiperating with one another to vary the reluctance of a magnetic circuit, means to move one of said members toward the other, compressible means to move the one member away from the other, said firstnamed means having a travel greater than the distance of separation of said members and including resilient means to absorb the excess travel of said firstnamed means, said resilient means opposing the compression of the second-named means. v

3. In anigniter, relatively movable mag netic members coeperating with each ct. er to vary the reluctance of a magnetic circuit, resilient means to separate said members a predetermined distance, a non-yielding reciprocable element by means of which said members are mo ed into engagement, said element having a stroke in excess of said distance, and resilient means permitting a relative yield' between the engaged members and against re 'memher approaches the reiaiable magnetic members said element, said last-named resilient means opposing the compression of the first-named resilient means.

4. In an ignite-r, relathiely movable mag netic members cooperating with each other to vary the reluctance of a n'iagnetic circuit, means to move one of said members toward the other and release it for subsequent movement at high speed away. from the latter, driving means compressible by the firstnamed means to effect the high speed movement, and a cushioning means engaging the movable member and opposing the action of said driving means, the tension of, the cushioning means increasing as that of the driving means diminishes on said high speed movement to yieldingly arrest the movable member. 5. In an igniter able magnetic memb another to vary the having relatively movers cooperating with one reluctance of a magnetic circuit, means to move one of said members to -and from the other member including cushioning means to yieldingly arrest one a member in its movement toward the other member. and cause the former to be gently seated on the latter, 6. In an igniter, having relatively movable magnetic members cooperating with each other to vary the reluctance of netic circuit, means to move one member into engagement with the other and te subse qnently release it for high speed movement away from the latter member, means comgir eslsihle .011 the first-nar'ned. movement to cfset the high speed movement when the movable memberis released, and a yieldconnection associated with the firs means and compressible as said inc-r preach one another to 1 relativel mevabie men-her n he gently den-send ,y in an i niter, havn able magnetic members r eacl': other to vary the netie circuit, means to Ward and ei member,- s, device through v mitted to the relative-:13; movable l? and means art-mg in conjur tion it first-nanied i ans to l e hecome compressed the rela lVGlZ) riiovable stationary member, whereby said members may be tli one another.

leer, having relatively movcoeperating with each other to vary the reluctance of a magnetic circuit, means ts move one member into ene'aejement with he ether and to subsneedjmcvemeat away from the latter member, said means in eluding a notary cam an-d'a iprocable eleiar membe elatively i rating with pand as the movable a. mag,

flux with ment "to ride on the periphery of the cam, a cushioning stop constantly engaged with the movable IDGIHbGI to yieldingly arrest the relatively movable member in its flight away from the other'member and to prevent said element from impinging against said cam when released for said high speed movement.

9. In an igniter, having relatively movable magnetic members coiSperat-ing \vlth each other-to vary the reluctance of a magnetic circuit, means to move one member toward and into engagement with the other including a ieciprocable element and a spring interposed between thelatter and the movable member, and means to move the latter away from the other element including a spring arranged tobe compressed as the members approach each other and subsequently exmember is released by the, first-named means, said first-named spring arranged to be compressed only after the second spring has been compressed and as the movable-member nears the other, member, whereby the two members may be gently brought into engagement.

'10. An igniter, comprising, a source of magnetic flux, means including a cooperating core and movable arnmture to provide a magnetic circuit from said source, primary and secondary generatin; windizws associated with said core, cob mating breaker points to which the terminals of the primary \vind' electrically roz'mer'red, saidarmature being movable away from said core to increase the reluctance of said circuii, means providinga shunt path for the a permanent air gap therein, so that the reluctance of such path is greater than the. minimum and less than the maximum reluctance of said circuit, and means to separate said breaker points duringits movement away from sa-i d core.

11.1311 igniter, comprising :1 source of magnetic flux, u'lcans including a coiiperab ing core and movable armature to provide a magnetic circuit from said source, means to disengage said core and armature and move the latter a predetermined distance away from the former to decrease the this in said circuit, primary and secondary generating windii'zgs ass'ceiated with said gore, own-aerating breaker points to which the terminalsof the primary Winding are electricallv connected, and means to separate said hreaa'er points after said armature has been disengaged from said core and before it has traveled said distance.

12. An igniter, comprising, a source of magnetic flux, means includinga cooperating core and movable armature to provide a'magnetic circuit from said source, means to disengage said core and armature and move the latter predetm'mined distance ting windings associated with said core trically connecte and means to separate said breaker points after said armature has been disengaged from said core and before it has traveled said distance, said lastnamed means arranged to hold the breaker points in separated relation for a predetermined time interval.

13. In an i iter, relatively separable magnetic mem rs cooperatin' with one 7 another to vary the reluctance o a magnetic circuit, resilient means tending when stressed to separate said members, means to move the members toward and into engagement with one another and thereby place said resilient'means under stress to subsequently separate said members, said second named means having a travehgreater than the distance of separation of said members, and a second resilient means tending when stressed to move the members toward one another in opposition to the first resilient means, said second resilient means being 1cm readily, stresser than the first resilient means and arranged to be gradually placed under stress as the members approach one another to retard the movement of the movable member relatively to "that .of said second named means.

14. In an igniter, relatively movable magnetic members cooperating with one another to vary the reluctance of a magnetic circuit, a spring acting on the movable member and tending when stressed to separate it from the other member,a second sprin less readil stressed than the first, name spring an actin on the movable member in'opposition to tie first named spring, and

means to move the movable member toward and into engagement with the other member, said 1ast-named means having a movement reater than the distance of separation 0 said members and transmitting its force to the movable member through the second named spring.

15. In an igniter, having a source of magnetic flux, means includin cooperating armature to provi e a magnetic circuit from said source, means to disengage the armature and move it a predetermined distance away from said core to interrupt the magnetic circuit, primary and secondary generating windings associated with said core, and cooperating breaker points electrically connected to the terminals of the primary winding, a fixed support for one of said breaker points, a movable member to which the other breaker point is attached,

yieldable means acting on the movable mem-' ber and tending to hold saidpoints in en gagement, and a part connected with the armature and partaking of its movement, said movable member having a portion located in the path of said part but spaced from the latter when said core and armature are enga ed, whereby the breaker points are separate armature and core.

, PHELPS BROWN.

a core and after the disengagement of the r 

